He said his office has asked GMA News for an authenticated video of the incident.

"Have asked GMA to authenticate but video that I saw was inconclusive. Didn’t actually see any bullying,” Roque said.

He said he sought for a written statement from the fishermen involved in the incident.

“Anyway, asked fishermen for their written statement," he said.

China has taken control of the Scarborough Shoal after a standoff between the Philippines and Chinese ships in April 2012.

Beijing has been claiming almost the entire South China Sea, including Scarborougg Shoal, which is within the 200 nautical miles exclusive economic zone of the Philippines.

The arbitral tribunal has invalidated China's historic and sovereign claim in almost the entire South China Sea and declared the Scarborough Shoal as a traditional fishing ground of the Filipino, Chinese and other fishermen.

Meanwhile, Roque said he stood by what President Rodrigo Duterte has said that he was not aware of the alleged harassment by the Chinese when the Philippine military was conducting resupply missions to Ayungin Shoal.

"I defer to his statement," Roque said.

Duterte, in a media interview shortly after his arrival from South Korea, said he could not comment on the alleged harassment as he had to check it first.

Magdalo Partylist Rep. Gary Alejano earlier disclosed that on May 11, China's navy and coast guard challenged the Philippine Navy's LS507 supplying troops stationed on BRP Sierra Madre, a rusty ship that the Philippine government has run aground in Ayungin to assert sovereignty over the area. Celerina Monte/DMS